1. Field of the Invention
The present invention relates to a display substrate, a method of manufacturing the display substrate, and a display device having the display substrate. More particularly, the present invention relates to a display substrate used for a display device, a method of manufacturing the display substrate, and a display device having the display substrate.
2. Description of the Related Art
A liquid crystal display (LCD) device, in general, includes a thin-film transistor (TFT) layer formed on a lower substrate, a color filter layer formed on an upper substrate facing the TFT layer and a liquid crystal layer interposed between the TFT layer and the color filter layer.
The TFT layer includes signal lines, a thin film transistor TFT, and a pixel electrode that drives a plurality of pixels. The signal lines, the TFT and the pixel electrode are formed on the lower substrate. The color filter layer includes a color filter, a black matrix and a common electrode. The color filter includes red (R), green (G) and blue (B) color filters. The black matrix is formed on a boundary portion between the color filters. The common electrode faces the pixel electrode.
In order to prevent display defects caused by a misalignment of the LCD device, an LCD device of a color filter on array (COA) substrate type has been devised. A color filter layer is formed on the TFT layer of the COA-type LCD device.
The color filter layer further includes a key pattern for an alignment between the TFT layer and the color filter layer. The color filter layer having the black matrix requires an overcoating layer for planarizing a surface of the color filter layer. As a result, a process of manufacturing the color filter layer is complicated and light transmittance is decreased by the overcoating layer.